1. Field of the Invention
The present teachings relate to a machine implemented method for estimating the solid phase potential of either positive or negative electrode of a battery. This machine implemented method includes estimating the solid phase potential by use of a multi-layer model of the electrode to derive the solid phase potentials, and utilizing voltage and current readings to update diffusion coefficients used by the multi-layer model to obtain a more accurate estimation of the solid phase potential. The method can be implemented on a processing device to control battery charging conditions over a charging regime to optimize the battery charging process.
2. Discussion of the Related Art
One known battery management system that determines the state of charge of the battery by receiving signals representative of physical quantities of the battery is set forth in U.S. Pat. No. 6,016,047. Another known method for determining various variables, including electrolyte concentration, of a battery subdivides the battery volume into at least two electrolyte volume components, and is set forth in U.S. Pat. No. 7,327,147.
One model used to estimate a battery's internal states is the Single Particle Battery model. This model is presented in detail in, at least, two technical papers, “Cycle Life Modeling of Lithium-Ion Batteries,” G. Ning, B. N. Popov, Journal of Electrochemical Society 151 (2004), pages A1584-A1591, and “Online estimation of the state of charge of a lithium ion cell,” S. Santhanagopalan, R. E. White, Journal of Power Sources 161 (2006), pages 1346-1355, both of which are incorporated herein in their entireties.
A need exists for a method that accurately determines the solid phase potential of both of the positive and negative electrodes of a battery which information can be utilized to control a battery charging system, which can in turn, lead to an improved energy storage device, particularly for automotive applications.